How can I right-align end-of-line comments with the Tabular plugin?

Question

I often have code that looks something like this:

a = 1 # description 1
longer_name = 2 # description 2
# no_longer_needed = 3 # ignore
another_name = 4 # description 4

and would like to right-align the right-hand annotations, including the annotations of "commented-out" lines, so that it looks something like this:

a = 1                  # description 1
longer_name = 2        # description 2
# no_longer_needed = 3 # ignore
another_name = 4       # description 4

How can I do so with the Tabular plugin?

Answer 1

Just figured this out and wanted to share with people. You can use

:Tabularize /^\s*\S.*\zs#

where the ^\s*\S.*\zs# is a vim regexp that matches only the last comment character, while ignoring matches that occur as the first non-whitespace character in each line e.g. "commented out" lines (try searching/highlighting it).

If you want to put a handy remap in your .vimrc, for example to <Leader>., just use

vnoremap <expr> <Leader>. ':Tabularize /^\s*\S.*\zs' . split(&commentstring, '%s')[0] . "<CR>"
nnoremap <expr> <Leader>. ':Tabularize /^\s*\S.*\zs' . split(&commentstring, '%s')[0] . "<CR>"

where the above aligns by the "start-of-comment" character for an arbitrary filetype.